Remove old synthetic source mapping config (elastic#115889) (elastic#115961)

This change replaces the old synthetic source config in mappings with 
the newly introduced index setting.

Closes elastic#115859

Author: dnhatn

modules/mapper-extras/src/internalClusterTest/java/org/elasticsearch/index/mapper/MatchOnlyTextMapperIT.java

@@ -12,6 +12,7 @@
 import org.elasticsearch.action.bulk.BulkRequestBuilder;
 import org.elasticsearch.action.bulk.BulkResponse;
 import org.elasticsearch.action.support.WriteRequest;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.mapper.extras.MapperExtrasPlugin;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.plugins.Plugin;
@@ -89,13 +90,14 @@ public void testHighlightingWithMatchOnlyTextFieldSyntheticSource() throws IOExc
         // load the source.
 
         String mappings = """
-            { "_source" : { "mode" : "synthetic" },
+            {
               "properties" : {
                 "message" : { "type" : "match_only_text" }
               }
             }
             """;
-        assertAcked(prepareCreate("test").setMapping(mappings));
+        Settings.Builder settings = Settings.builder().put(indexSettings()).put("index.mapping.source.mode", "synthetic");
+        assertAcked(prepareCreate("test").setSettings(settings).setMapping(mappings));
         BulkRequestBuilder bulk = client().prepareBulk("test").setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);
         for (int i = 0; i < 2000; i++) {
             bulk.add(

modules/mapper-extras/src/test/java/org/elasticsearch/index/mapper/extras/MatchOnlyTextFieldMapperTests.java

@@ -64,19 +64,19 @@ protected Object getSampleValueForDocument() {
     }
 
     public void testExistsStandardSource() throws IOException {
-        assertExistsQuery(createMapperService(testMapping(false)));
+        assertExistsQuery(createMapperService(fieldMapping(b -> b.field("type", "match_only_text"))));
     }
 
     public void testExistsSyntheticSource() throws IOException {
-        assertExistsQuery(createMapperService(testMapping(true)));
+        assertExistsQuery(createSytheticSourceMapperService(fieldMapping(b -> b.field("type", "match_only_text"))));
     }
 
     public void testPhraseQueryStandardSource() throws IOException {
-        assertPhraseQuery(createMapperService(testMapping(false)));
+        assertPhraseQuery(createMapperService(fieldMapping(b -> b.field("type", "match_only_text"))));
     }
 
     public void testPhraseQuerySyntheticSource() throws IOException {
-        assertPhraseQuery(createMapperService(testMapping(true)));
+        assertPhraseQuery(createSytheticSourceMapperService(fieldMapping(b -> b.field("type", "match_only_text"))));
     }
 
     private void assertPhraseQuery(MapperService mapperService) throws IOException {
@@ -104,13 +104,6 @@ protected void registerParameters(ParameterChecker checker) throws IOException {
         );
     }
 
-    private static XContentBuilder testMapping(boolean syntheticSource) throws IOException {
-        if (syntheticSource) {
-            return syntheticSourceMapping(b -> b.startObject("field").field("type", "match_only_text").endObject());
-        }
-        return fieldMapping(b -> b.field("type", "match_only_text"));
-    }
-
     @Override
     protected void minimalMapping(XContentBuilder b) throws IOException {
         b.field("type", "match_only_text");
@@ -256,7 +249,7 @@ public void testDocValues() throws IOException {
     }
 
     public void testDocValuesLoadedFromSynthetic() throws IOException {
-        MapperService mapper = createMapperService(syntheticSourceFieldMapping(b -> b.field("type", "match_only_text")));
+        MapperService mapper = createSytheticSourceMapperService(fieldMapping(b -> b.field("type", "match_only_text")));
         assertScriptDocValues(mapper, "foo", equalTo(List.of("foo")));
     }
 

server/src/test/java/org/elasticsearch/index/mapper/DocCountFieldMapperTests.java

@@ -84,12 +84,12 @@ public void testInvalidDocument_ArrayDocCount() throws Exception {
     }
 
     public void testSyntheticSource() throws IOException {
-        DocumentMapper mapper = createDocumentMapper(syntheticSourceMapping(b -> {}));
+        DocumentMapper mapper = createSytheticSourceMapperService(topMapping(b -> {})).documentMapper();
         assertThat(syntheticSource(mapper, b -> b.field(CONTENT_TYPE, 10)), equalTo("{\"_doc_count\":10}"));
     }
 
     public void testSyntheticSourceMany() throws IOException {
-        MapperService mapper = createMapperService(syntheticSourceMapping(b -> b.startObject("doc").field("type", "integer").endObject()));
+        MapperService mapper = createSytheticSourceMapperService(mapping(b -> b.startObject("doc").field("type", "integer").endObject()));
         List<Integer> counts = randomList(2, 10000, () -> between(1, Integer.MAX_VALUE));
         withLuceneIndex(mapper, iw -> {
             int d = 0;
@@ -116,7 +116,7 @@ public void testSyntheticSourceMany() throws IOException {
     }
 
     public void testSyntheticSourceManyDoNotHave() throws IOException {
-        MapperService mapper = createMapperService(syntheticSourceMapping(b -> b.startObject("doc").field("type", "integer").endObject()));
+        MapperService mapper = createSytheticSourceMapperService(mapping(b -> b.startObject("doc").field("type", "integer").endObject()));
         List<Integer> counts = randomList(2, 10000, () -> randomBoolean() ? null : between(1, Integer.MAX_VALUE));
         withLuceneIndex(mapper, iw -> {
             int d = 0;

server/src/test/java/org/elasticsearch/index/mapper/IgnoredSourceFieldMapperConfigurationTests.java

@@ -130,8 +130,8 @@ private MapperService mapperServiceWithCustomSettings(
         for (var entry : customSettings.entrySet()) {
             settings.put(entry.getKey(), entry.getValue());
         }
-
-        return createMapperService(settings.build(), syntheticSourceMapping(mapping));
+        settings.put(SourceFieldMapper.INDEX_MAPPER_SOURCE_MODE_SETTING.getKey(), SourceFieldMapper.Mode.SYNTHETIC);
+        return createMapperService(settings.build(), mapping(mapping));
     }
 
     protected void validateRoundTripReader(String syntheticSource, DirectoryReader reader, DirectoryReader roundTripReader)